For those who aren't already aware, Aldi's and Trader Joe's are owned by the same German company. From the little that I know, TJ's got it's business plan from the Aldi model but took a more trendy path to attract a different group of consumers. In other words, I took that to mean Aldi's stuck closer to the German model when implemented here in the US and TJ's put an American twist on theirs.
Recent reports and comparisons to other retail establishments states that they pay their employees quite well. I guess that's why TJ's cashiers seem so happy when I shop there.